1. Field of the Disclosure
The disclosure is generally related to pressure regulators and more specifically to sliding gate pressure regulators.
2. Related Technology
Pressure regulators are used in myriad industrial and residential applications for controlling the downstream pressure of a fluid. For example, in chemical processing plants or oil refineries, pressure regulators are used to manipulate a flowing fluid to compensate for increases or decreases in demand, or other load disturbances, and thus keep the fluid pressure regulated. Similarly, pressure regulators may be used in plumbing fixtures to maintain a pre-determined pressure of fluid that automatically adjusts to variations in demand, such as anti-scald valves in showers or faucets. By controlling downstream pressure, pressure regulators compensate for variations in downstream demand. For example, as downstream demand increases, pressure regulators open to allow more fluid to flow, thus maintaining a relatively constant downstream pressure. On the other hand, as downstream demand decreases, pressure regulators close to reduce the amount of fluid flowing, again maintaining a relatively constant downstream pressure.
One type of pressure regulator is the sliding gate regulator. The sliding gate regulator includes a sliding gate and a stationary plate. Together, these two parts cooperate to regulate the flow of fluid through the regulator.
Generally speaking, the sliding gate is moved across the surface of the stationary plate by a disc pin. When throttled open, openings disposed in the slidable gate and openings disposed in the stationary plate cooperate to allow fluid to flow through the plates. Because the fluid flow path is straight through the slots (i.e., the flow path does not bend or turn), turbulence, noise, and wear are reduced. Because the slidable gate is supported from behind by the stationary plate, the slidable gate and the stationary plate are not disturbed by unbalanced forces, which are characteristic of single seated globe valves, in the closed or nearly closed position. As a result, sliding gate regulators generally achieve higher rangeability than can be achieved with a similar sized globe style valve.
A typical sliding gate regulator 10 is illustrated in FIG. 1. The sliding gate regulator 10 includes a valve body 12 having two pieces 12a, 12b attached to one another. The valve body 12 includes a fluid inlet 14 and a fluid outlet 16 connected by a flow path 18. The flow path 18 defines an opening 20 that is sized to receive the sliding gate 22 and the stationary plate 24.
An actuator 30 provides motive force to move the sliding gate 22. The actuator 30 may include an actuator housing 32 that defines an inner chamber 34. The inner chamber 34 may be divided into a pressurized chamber 36 and an unpressurized chamber 38 by a diaphragm 40. A biasing spring 42 may be disposed in the unpressurized chamber 38. The biasing spring 42 may be disposed between a diaphragm seat 44 and an adjustable spring seat 46. The adjustable spring seat 46 may be moved by an adjustment screw 48 to vary the force provided by the biasing spring 42. The diaphragm 40 may be connected to the diaphragm seat 44 by a diaphragm plate 50. The diaphragm plate 50 is attached to a valve stem 52, which is connected to the slidable gate 22 by a connector pin 53.
The biasing spring 42 moves the slidable gate 22 in response to changes in fluid pressure in the pressurized chamber 36. The valve stem 52 includes a valve pin 54 that extends through the stationary plate 24 and that is connected to the slidable gate 22 by the connector pin 53. Thus, the slidable gate 22 reciprocates within the opening 20 in response to forces provided by the biasing spring 42.
When the regulator is closed, the slidable gate 22 and the stationary plate 24 form a solid barrier to flow. The upstream pressure keeps the slidable gate 22 and the stationary plate 24 in constant contact, which eliminates noisy chattering often encountered during valve operation.
Generally, the stroke of a sliding gate regulator is about ⅓ the length of the stroke of a similarly sized globe style valve. As a result, the sliding gate regulator has a fast response, reduced droop, longer diaphragm life and greater sensitivity than similarly sized glove style valves. The slidable gate requires little travel to move from fully open to fully closed, and quickly corrects pressure or temperature deviations.
While known sliding gate regulators may have higher flow rates and less noise than similarly sized globe valves, known sliding gate valves are difficult to maintain. More specifically, the sliding gate and stationary plate are difficult to access without removing the regulator from the flow line. Additionally, the disk pin connection to the slidable gate limits the size and orientation of the openings in the slidable gate, thereby limiting the overall flow volumes that are achievable by the sliding gate regulator.